Probe for scanning microscope produced by focused ion beam machining

ABSTRACT

The present invention realizes a probe for a scanning type microscope by which the quality of a nanotube probe needle can be improved by means of fastening and cutting the nanotube probe needle, furthermore by means of implanting ions of another element. For the object, a probe for a scanning type microscope produced by a focusing ion beam related to the present invention is characterized in that, in a probe for a scanning type microscope which captures substance information of the surface of a specimen by the tip end  14   a  of a nanotube probe needle  12  fastened to a cantilever  4,  an organic gas G is decomposed by a focused ion beam I in a focused ion beam apparatus  2,  and the nanotube  12  is bonded to the cantilever  4  with a deposit of the decomposed component thus produced. Furthermore, the present invention provides a probe for a scanning type microscope by which the quality of the nanotube probe needle can be improved by means of removing an unnecessary deposit  24  adhering to the nanotube tip end portion  14  using a ion beam I, by means of cutting an unnecessary part of the nanotube in order to control length of the probe needle and by means of injecting ions into the tip end portion  14  of the nanotube.

TECHNICAL FIELD

[0001] The invention is related to a probe for a scanning typemicroscope which images a surface structure of a specimen, whereinnanotubes such as a carbon nanotube, BCN (boron carbon nitride) seriesnanotube, BN (boron nitride) series nanotube, etc. are used for theprobe needle, in more detail, related to a probe for a scanning typemicroscope produced by focused ion beam machining which is manufacturedby means of processes such as the nanotube of fastening, purifying andcutting using a focused ion beam apparatus.

BACKGROUND ART

[0002] In order to image a surface structure of a specimen by an atomicforce microscope abbreviated as AFM, a scanning needle is needed whichis caused to approach to the surface of the specimen for gettinginformation from it. As the scanning needle, a cantilever made ofsilicon or silicon-nitride, on the tip of which a protruding portion (orpyramid portion) is formed, has been known in the past.

[0003] A conventional cantilever is formed by means of themicro-fabrication technique such as lithography, etching, etc. Since thecantilever detects atomic force from the surface of specimen by the tipof protruding portion, the degree of cleanness of an image is determinedby the degree of sharpness of the tip portion. Then, in the sharpeningtreatment of the tip end of the protruding portion serving as a probeneedle, an oxide process and an etching process for an oxide film whichare sort of semi-conductor process technique are utilized. However,there is a lower limit in a reduction of size even in the semi-conductorprocess technique, so that the degree of sharpness of the tip end of theprotruding portion described above is also physically limited.

[0004] On the other hand, a carbon nanotube was discovered as a carbonmatter having a new structure. The carbon nanotube is from about 1 nm toseveral 10 nm in diameter and several μm in length, and its aspect ratiois around 100˜1000. It is difficult to form a probe needle of 1 nmdiameter by means of the present technique of semiconductor. Therefore,in this respect, the carbon nanotube provides best condition for theprobe needle of an AFM.

[0005] In such a situation, H. Dai and others published, in Nature(Vol.384, Nov. 14, 1996), a report with respect to an AMF probe in whicha carbon nanotube is stuck on the tip of the protruding portion of acantilever. Though the probe proposed by them was of epoch-making, thecarbon nanotube fell off from the protruding portion during repeatedlyscanning surfaces of specimens, since the carbon nanotube was simplystuck on the protruding portion

[0006] In order to solve this weak point, the present inventors haveachieved to develop a method fastening firmly the carbon nanotube to theprotruding portion of the cantilever. Results of this invention havebeen published as the Japanese patent application laid-open (Kokai) Nos.2000-227435 and 2000-249712.

[0007] The first fastening method above-mentioned is that a coating filmis formed in an electron microscope by irradiating an electron beam tothe base end portion of a nanotube, and next the nanotube is fastened tothe cantilever by means of covering the nanotube with the coating film.The second method is that the base end portion of the nanotube isfusion-fastened to the protruding portion of the cantilever byirradiating an electron beam on the base end portion of the nanotube orby causing to flow current, in an electron microscope.

[0008] It is a quite skilful method to fasten by coating orfusion-welding a nanotube base end portion using an electron beam, whileenlarging an object image by means of an electron microscope. However,there is a limit in energy intensity of an electron beam of the electronmicroscope, so that this fact causes to yield a limit forcoating-strength or fusion-welding-strength, and as the result, it wasdifficult to obtain fastening-strength beyond a certain degree.

[0009] Besides, lengths of nanotubes produced by an arc-discharge areinhomogeneous, so that it is necessary finally to homogenize quality ofthe nanotube products by unifying the lengths of the nanotubes. However,due to the above limit in the electron microscope, the cutting processof the nanotube has difficult points, so that the control of thenanotube length was not enough well done.

[0010] Furthermore, since an electron microscope is a device fortreating electron beams, though it is possible to irradiate an electronbeam, but being impossible to diffuse atoms of another element, or toimplant ions into a probe needle nanotube, therefore, the improvement ofthe quality of nanotubes has not been progressed

[0011] The essential aim of the electron microscope is to obtainenlarged images of specimens in a clean imaging room being in the vacuumstate. However, when an organic gas flows into this electron microscopeand decomposes, a body-tube and the imaging room, which should be clean,are polluted with the organic gas or the decomposed matter. If thispollution gas is absorbed in and re-emitted from a wall-surface, the gasadheres to a surface of a cantilever. But, since it is difficult toremove the adhered pollution matter by an electron beam, this fact showsthat there is a technical limit of the electron microscope, inmanufacture of the nanotube probe needle.

[0012] Accordingly, an object of the present invention is to find anapparatus other than the electron microscope as a device in which thenanotube is fastened to a protruding portion of a cantilever, and toprovide a probe for a scanning type microscope which can fasten and cuta nanotube probe needle and furthermore can improve the quality of thenanotube probe needle by implanting another element atoms, etc.

DISCLOSURE OF INVENTION

[0013] The present invention of claim 1 provides, in a probe for ascanning type microscope, by which substance information of a specimenis obtained by means of a tip end of a nanotube probe needle fastened toa cantilever, a probe for a scanning type microscope produced by focusedion beam machining, which is characterized in that the nanotube isfastened to a cantilever with a decomposed deposit produced bydecomposing an organic gas by means of a focused ion beam in a focusedion beam apparatus.

[0014] The present invention of claim 2 provides a probe for a scanningtype microscope described in the first part of the present invention,wherein a hydrocarbon is used for the above described organic gas.

[0015] The present invention of claim 3 provides a probe for a scanningtype microscope described in the first part of the present invention,wherein an organic-metallic gas is used for the above described organicgas.

[0016] The present invention of claim 5 provides a probe for a scanningtype microscope described in the first part of the present invention,wherein a silicon cantilever, a silicon-nitride cantilever or acantilever coated with a conductive substance are utilized as the abovedescribed cantilever.

[0017] The present invention of claim 5 provides a probe for thescanning microscope produced by focused ion beam machining which ischaracterized in that unnecessary matter existing in a predeterminedregion is removed by irradiating an ion beam to the predetermined regionof a nanotube probe needle fastened to the cantilever.

[0018] The present invention of claim 6 provides a probe for a scanningtype microscope described in the fifth part of the present invention,wherein the above described unnecessary matter is a unnecessary depositheaping up at a tip end portion of the nanotube probe needle or aunnecessary deposit heaping up near a base end portion of the nanotube.

[0019] The present invention of claim 7 provides a probe for thescanning microscope produced by focused ion beam machining which ischaracterized in that an unnecessary part of the nanotube probe needleis cut off and the length of tip end portion of the nanotube probeneedle is controlled by irradiating an ion beam to the tip end portionof the nanotube probe needle fastened to the cantilever.

[0020] The present invention of claim 8 provides a probe for a scanningtype microscope described in the seventh part of the present invention,wherein the nanotube is cut in a perpendicular or an oblique direction,in the cutting of the unnecessary part above described.

[0021] The present invention of claim 9 provides a probe for thescanning microscope produced by focused ion beam machining which ischaracterized by changing physical and chemical qualities of the probeneedle by irradiating an ion beam to the predetermined region of the tipend portion of the nanotube probe needle fastened to the cantilever.

[0022] The present invention of claim 10 provides a probe for a scanningtype microscope described in the ninth part of the present invention,wherein the above described ion element is fluorine, boron, gallium, orphosphorus.

[0023] The present inventors had earnestly investigated a device beingsubstituted for an electron microscope, and as the result, had gotten anidea to use an ion beam instead of an electron beam; specifically hadachieved an idea to utilize a focused ion beam apparatus (abbreviated asFIB apparatus) which can focus at will the ion beam and can process anobject.

[0024] This FIB apparatus is a device by which various atoms areionized, the ions are accelerated by means of an applied electric field,and this ion beam is focused by means of an electric field lens so thatthe beam section is made fine and the beam comes to be a high energystate, and by which a target is processed by means of irradiating theresultant focused ion beam to the target. Accordingly, the FIB apparatuscomprises partial devices such as an ion source, an accelerationapparatus, a beam-focusing apparatus and a beam-operating device, etc.

[0025] An applied voltage can be freely arranged, and the energy of theion beam can be arbitrarily set up by the acceleration apparatus.Various processes for nanotubes are possible by means of arrangement ofthe energy of the ion beam. By the present invention, an organic gaswhich is induced into a reaction chamber of the FIB apparatus isdecomposed by the ion beam. Leaving a nanotube base end portion adheredto a protruding portion of a cantilever disposed in the reactionchamber, the above described decomposed gas heaps up on this base endportion, so that the nanotube is strongly fastened to the protrudingportion of the cantilever by this decomposed deposit. In this manner,the ˜ related to the present invention is accomplished.

[0026] In a case where the organic gas is a hydrocarbon gas, the abovedescribed decomposed deposit is a carbon deposit, and the nanotube isfastened to the protruding portion by means of this carbon deposit. In acase where the organic gas is an organic-metallic gas, the abovedescribed decomposed deposit is a metallic deposit, and the nanotube isfastened in a conductive state to the protruding portion by means ofthis metallic deposit.

[0027] As substances of the above-described hydrocarbon series, thereare hydrocarbons of methane series, hydrocarbons of ethylene series,hydrocarbons of acetylene series, cyclic hydrocarbons, etc.; moreconcretely saying, hydrocarbons of less molecular-weight such asethylene or acetylene are favorable among them. Furthermore, as theabove-described organic-metallic gases, the following gases can beutilized; for examples, W(CO)₆, Cu(hfac)₂, (hfac:hexa-flouro-acetyl-acetonate), (CH₃)₂AlH, Al(CH₂—CH)(CH₃)₂, [(CH₃)₃Al]₂,(C2H₅)₃Al, (CH₃)₃Al, (I—C₄H₉)₃Al, (CH₃)₃AlCH₃, Ni(CO)₄, Fe(CO)₄,Cr[C₆H₅(CH₃)₂], Mo(CO)₆, Pb(C₂H₅)₄, Pb(C₅H₇O₂)₂, (C₂H₅)₃PbOCH₂C(CH₃)₂,(CH₃)₄Sn, (C₂H₅)₄Sn, Nb(OC₂H₅)₅, Ti(i-OC₃H₇)₄, Zr(C₁₁H₁₉O₂)₄,La(C₁₁H₁₉O₂)₃, Sr[Ta(OC₂H₅)₆]₂, Sr[Ta(OC₂H₅)₅(Oc₂H₄OcH₃)]₂,Ba(C₁₁H₁₉O₂)₂, (Ba,Sr)₃₍C₁₁H₁₉O₂), Pb(C₁₁H₁₉O₂)₂, Zr(OtC₄H₉)₄,Zr(OiC₃H₇)(C₁₁H₁₉O₂)₃, Ti(OiC₃H₇)₂(C₁₁H₁₉O₂), Bi(OtC₅H₁₁)₃, Ta(OC₂H₅)₅,Ta(OiC₃H₇)₅, Nb(OiC₃H′)₅, Ge(OC₂H₅)₄, Y(C₁₁H₁₉O₂)₃, Ru(C₁₁H₁₉O₂)₃,Ru(C₅H₄C₂H₅)₂, Ir(C₅H₄C₂H₅)(C₈H₁₂), Pt(C₅H₄C₂H₅)(CH₃)₃, Ti[N(CH₃)₂]₄,Ti[N(C2H5)2]4, As(OC₂H₅)₃, B(OC₂H₃)₃, Ca(OCH₃)₂, Ce(OC″H₅)₃,Co(OiC₃H₇)₂, Dy(OiC₃H₇)₂, Er(OiC₃H₇)₂, Eu(OiC₃H₇)₂, Fe(OCH₃)₃,Ga(OCH₃)₃, Gd(OiC₃H₇)₃, Hf(OCH₃)₄, In(OCH₃)₃, KOCH₃, LiOCH₃, Mg(OCH₃)₂,Mn(OiC₃H₇)₂, NaOCH₃, Nd(OiC₃H₇)₃, Po(OCH₃)₃, Pr(OiC₃H₇)₃, Sb(OCH₃)₃,Sc(OiC₃H₇)₃, Si(OC₂H₅)₄, VO(OCH₃)₃, Yb(OiC₃H₇)₃, Zn(OCH₃)₂, etc.

[0028] As for the nanotube, there are a conductive carbon nanotube or aninsulation nanotube of BN series and of BCN series. And as for thecantilever for an AFM, there are a semi-conduction silicon cantileverand an insulation silicon-nitride cantilever. But a conductivecantilever can be manufactured by coating on a cantilever surfaceincluding the protruding portion with a conductive film such as metal,etc. and in the similar manner, the insulation nanotube can betransmuted to a conductive nanotube.

[0029] Accordingly, a conductive probe for an ion type scanning typemicroscope can be manufactured by means of electrically connection ofthe conductive nanotube with the conductive cantilever using aconductive deposit such as a metallic deposit. The conductive probe,owing to its conductivity, can be utilized not only for the AFM but alsofor a STM (tunneling microscope) which detects a tunnel-current.However, if the semi-conduction cantilever or the insulation cantileveris used as a cantilever, the cantilever, due to non-conductivity, can beused as the probe for an ordinary AFM which detects flexion.

[0030] As for the probe for the scanning type microscope related to thepresent invention, there are not only the above-described AFM and STM,but also a level force microscope (LFM) which detects differences of asurface by means of friction force, a magnetic force microscope (MFM)which detects magnetic interaction, an electric-field force microscope(EFM) which detects a gradient of an electric field, and a chemicalforce microscope (CFM) which images surface distribution of a chemicalfunction group. All such microscopes are for obtaining surfaceinformation of specimens at the atomic level.

[0031] The tip end of a nanotube is a probe needle for detection. If anunnecessary deposit adheres to the tip end of the nanotube, this portionworks as a probe needle so that the tip end of the nanotube captureserror information and the image is caused to be dim. Accordingly, theunnecessary deposit adhering to the nanotube tip end portion is removedby means of ion beam irradiation, by increasing the ion beam energy ofthe FIB apparatus higher.

[0032] As was described above, in the present invention, the tip endportion of the nanotube is fastened to the protruding portion of thecantilever by means of the decomposed deposit. In a case where thisdecomposed deposit is formed to expand up to an unnecessary region,second processes such as a formation of a conductive film, etc. arecaused to be difficult. In such a case, this unnecessary decomposeddeposit near the base end portion can be removed by means of irradiationof a focused ion beam.

[0033] Length of produced nanotubes is in general quite indefinite.However, in order to unify nanotube quality, it is necessary to makeuniform the lengths of the nanotube tip ends. Then, by solution-cuttingthe unnecessary parts of the nanotubes by means of the ion beam, thelength of the nanotube is controlled. For this purpose, the energy ofthe ion beam is increased or an irradiation period is arranged.

[0034] In addition, in order to improve a quality of the nanotube tipend, ions can be shot into the nanotube by the FIB apparatus. Ionsaccelerated in high energy can be shot into the inner space of thenanotube, but low energy ions is driven on a surface layer of thenanotube and coats the surface of the nanotube. Particularly, when ionsare shot into the tip end of the nanotube probe needle, these ionsdirectly act to a surface of a specimen.

[0035] As the sort of the ion, an arbitrary element can be chosen, forexamples, such as fluorine, boron, gallium, or phosphorus, etc. Theseatoms react on a carbon atom in the nanotube to form CF-combination,CB-combination, CGa-combination or CP-combination, which come to possessspecific properties for these combinations.

[0036] In a case where the ions shot into the tip end of the nanotubeare ferromagnetic atoms such as Fe, Co, Ni, etc., this probe for ascanning type microscope can be utilized for an MFM. That is, sincethese ferromagnetic atoms detect ferromagnetism of a surface of aspecimen at the atomic level, this technique can greatly contribute tothe progress of substance engineering such as the resolution of magneticstructure of a sample substance, etc.

BRIEF DESCRIPTION OF DRAWINGS

[0037]FIG. 1 is a schematic diagram of an apparatus, by which a probefor a scanning type microscope is manufactured using a focused ion beam.

[0038]FIG. 2 is a schematic diagram explaining an accomplished probe foran ion type scanning microscope.

[0039]FIG. 3 is a schematic diagram explaining a probe for an ion typescanning microscope in which a conductive cantilever is used.

[0040]FIG. 4 is a schematic diagram explaining a method to remove anunnecessary deposit by using a focused ion beam.

[0041]FIG. 5 is a schematic diagram explaining a method to controllength of nanotube by means of a focused ion beam.

[0042]FIG. 6 is a schematic diagram explaining a case where a nanotubeis cut in an oblique direction.

[0043]FIG. 7 is a schematic diagram explaining a case where a quality ofa nanotube tip end portion is improved.

BEST MODE FOR CARRYING OUT THE INVENTION

[0044] In the following modes of probe for the scanning microscopeproduced by focused ion beam machining according to the presentinvention will be described in detail with reference to the accompanyingdrawings.

[0045]FIG. 1 is a schematic diagram showing an apparatus by which aprobe for a scanning type microscope is manufactured by using a focusedion beam. In the focused ion beam apparatus 2, a cantilever 4 isdisposed, and this cantilever 4 comprises a cantilever portion 6 and aprotruding portion 8 called a pyramidal portion.

[0046] The base end portion 16 of the nanotube 12 is adhered on asurface 10 of the protruding portion 8 and a tip end portion 14 isdisposed in a protruding fashion on the surface 10. The nanotube 12 maybe adhered in the focused ion beam apparatus 2, or may be disposed inthe focused ion beam apparatus 2, after being adhered in an electronmicroscope which is not drawn here.

[0047] An organic gas G is driven from outside into the focused ion beamapparatus 2, and is caused to flow to the arrow direction a. Thisorganic gas G is absorbed to adhere to near the nanotube 12, and anadhesion matter 18 a of the organic gas is formed. The organic gas G isdecomposed when a focused ion beam I is irradiated in the arrowdirection b against the adhesion matter of the organic gas, so thatlight molecules D such as a hydrogen component, etc. are scattered inthe dotted line direction. On the other hand, decomposed components suchas a carbon component and a metallic component, etc. heap up near thebase end portion 16 of the nanotube 12 to form a decomposed deposit 18.The cantilever 6 and the probe 12 are combined by this decomposeddeposit 18 and the probe for the scanning type microscope 20 (hereaftercalled probe 20) is accomplished.

[0048]FIG. 2 is a schematic diagram showing an accomplished probe forthe scanning microscope produced by focused ion beam machining. The baseend portion 16 of the nanotube 12 is firmly fastened to the surface 10of a protruding portion by a decomposed deposit 18. The durability ofthe probe 20 depends on the fastening strength of the decomposed deposit18 which serves as a coating film. The fastening strength of thedecomposed deposit 18 is decided by the denseness of the decomposeddeposit 18 and the fitness (combination degree) of the decomposeddeposit 18 to the surface 10 of the protruding portion.

[0049] The decomposed deposit formed carbon film, when gases ofhydrocarbon series such as an ethylene, an acetylene, a methane, etc.are used as the organic gas. The carbon film comprises amorphous carbonand is conductive in a case where the film thickness is extremely thin.Accordingly, making the carbon film thin, the nanotube 12 and thecantilever 4 can be set so as to be electrically connected through thecarbon film.

[0050] Furthermore, when an organic-metallic gas is used for the organicgas, a metallic component is produced as a decomposed component in acollision-decomposition reaction of the gas with an ion beam, and themetal heaps up near the nanotube base end portion 16 and forms a metalfilm which composes the decomposed deposit. In the same manner as theabove described carbon film, the nanotube 12 and the cantilever 4 can beset in an electrically connected state through the metal film.

[0051] As described above, the following gases can be utilized asorganic-metallic gases; for examples, W(CO)₆, Cu(hfac)₂, (hfac:hexa-flouro-acetyl-acetonate), (CH₃)₂AlH, Al(CH₂—CH)(CH₃)₂, [(CH₃)₃Al]₂,(C2H₅)₃Al, (CH₃)₃Al, (I—C₄H₉)₃Al, (CH₃)₃AlCH₃, Ni(CO)₄, Fe(CO)₄,Cr[C₆H₅(CH₃)₂], Mo(CO)₆, Pb(C₂H₅)₄, Pb(C₅H₇O₂)₂, (C₂H₅)₃PbOCH₂C(CH₃)₂,(CH₃)₄Sn, (C₂H₅)₄Sn, Nb(OC₂H₅)₅, Ti(i-OC₃H₇)₄, Zr(C₁₁H₁₉O₂)₄,La(C₁₁H₁₉O₂)₃, Sr[Ta(OC₂H₅)₆]₂, Sr[Ta(OC₂H₅)₅(Oc₂H₄OcH₃)]₂,Ba(C₁₁H₁₉O₂)₂, (Ba,Sr)₃₍C₁₁H₁₉O₂), Pb(C₁₁H₁₉O₂)₂, Zr(OtC₄H₉)₄,Zr(OiC₃H₇)(C₁₁H₁₉O₂)₃, Ti(OiC₃H₇)₂(C₁₁H₁₉O₂), Bi(OtC₅H₁₁)₃, Ta(OC₂H₅)₅,Ta(OiC₃H₇)₅, Nb(OiC₃H′)₅, Ge(OC₂H₅)₄, Y(C₁₁H₁₉O₂)₃, Ru(C₁₁H₁₉O₂)₃,Ru(C₅H₄C₂H₅)₂, Ir(C₅H₄C₂H₅)(C₈H₁₂), Pt(C₅H₄C₂H₅)(CH₃)₃, Ti[N(CH₃)₂]₄,Ti[N(C2H5)2]4, As(OC₂H₅)₃, B(OC₂H₃)₃, Ca(OCH₃)₂, Ce(OC″H₅)₃,Co(OiC₃H₇)₂, Dy(OiC₃H₇)₂, Er(OiC₃H₇)₂, Eu(OiC₃H₇)₂, Fe(OCH₃)₃,Ga(OCH₃)₃, Gd(OiC₃H₇)₃, Hf(OCH₃)₄, In(OCH₃)₃, KOCH₃, LiOCH₃, Mg(OCH₃)₂,Mn(OiC₃H₇)₂, NaOCH₃, Nd(OiC₃H₇)₃, Po(OCH₃)₃, Pr(OiC₃H₇)₃, Sb(OCH₃)₃,Sc(OiC₃H₇)₃, Si(OC₂H₅)₄, VO(OCH₃)₃, Yb(OiC₃H₇)₃, Zn(OCH₃)₂, etc.

[0052] As to the deposit 18, not only conductive deposits such as theabove described carbon film and metal film but also an insulationdeposit and a semi-conduction deposit are included. When gases ofhydrocarbon series or organic-metallic gases heap up to be in asemi-decomposition state, these tend to form insulation deposits. In acase of a silicon film, according to the crystal type of the film,various deposits are formed, i.e. from a semi-conduction deposit to aninsulation deposit.

[0053]FIG. 3 is a schematic diagram showing a probe for a scanning typemicroscope using a conductive cantilever. A conductive cantilever iscomposed by means of forming an electrode film 22 on the cantilever 4.As a nanotube 12, a conductive carbon nanotube is used, then thenanotube 12 and the cantilever4 are electrically connected each otherthrough a conductive deposit 18, so that a voltage can be appliedbetween a specimen and the nanotube 12 though an external power supplywhich is not shown in the diagram.

[0054] Describing it in detail, as the nanotube 12, there are, forexamples, a conductive carbon nanotube, an insulation BN seriesnanotube, a BCN series nanotube, etc. Also, as the cantilever 4, thereare a conductive cantilever, a semi-conduction silicon cantilever, aninsulation silicon-nitride cantilever, etc. Furthermore, as the deposit18, there are a conductive deposit, a semi-conduction deposit and aninsulation deposit.

[0055] Though the nanotube 12 seems to contact with a protruding surface10 of the cantilever, depending on the magnitude of electric contactresistance or due to the existence of interposition, both are notnecessarily electrically connected. Then, the electric property of thedeposit 18 connecting both is important. Therefore, according to the wayof combination of the nanotube 12, the deposit 18 and the cantilever 4,either the electric connection or disconnection between the nanotube 12and the cantilever 4 is certainly decided.

[0056]FIG. 4 is a schematic diagram showing the method to remove anunnecessary deposit by using a focused ion beam. Decomposed gases of theorganic gas form not only the deposit 18 which fastens a nanotube butalso occasionally an unnecessary deposit 24 by adhering to the tip endportion of the nanotube 12. The unnecessary deposit 24 thus producedcauses to reduce the imaging power of the nanotube 12.

[0057] Therefore, the unnecessary deposit 24 is scattered as shown bydotted arrow-lines by irradiating the focused ion beam I in thedirection of the arrow c against the unnecessary deposit 24. As theresult, only a tip end 14 a is remained at the probe needle point of thenanotube 12, so that the imaging power can be recovered. In this manner,the unnecessary deposit on the nanotube 12 or the cantilever 4 can beremoved by using the focused ion beam I.

[0058]FIG. 5 is a schematic diagram showing a method to control nanotubelength by using a focused ion beam. The length of nanotube 12 isspreading over from nano-order to micron-order. When the tip end portionof the nanotube 12 is long, the tip end portion oscillates, so that asharp image of the surface of specimen cannot be obtained. Therefore, inorder to unify the operation quality of a probe 20 and to increase itsefficiency, it is necessary to uniform the length of the tip end portion14 of the nanotube. Then, in order to control the length of the tip endportion 14 of the nanotube, the unnecessary portion should be cut off.

[0059] For the cutting off, solution-cutting force of the focused ionbeam is utilized. Since an energy density of the ion beam can becontrolled by increasing acceleration energy or by increasing a degreeof focusing of the focused ion beam, it is possible to give the energydensity enough for solution-cutting off the nanotube to the focused ionbeam I. When this focused ion beam is irradiated against a cut region Pin the arrow direction d, the cut region P melts and the tip end portionis cut off like a cut peace 14 b. Thus, the section turns to a new tipend 14 a. In this example, the section is perpendicular against an axisdirection of the nanotube 12.

[0060]FIG. 6 is a schematic diagram showing a method to cut obliquelythe nanotube. In this case, the focused ion beam I is irradiated in anoblique direction (arrow direction e) against the nanotube 12. By meansof this oblique cut, the tip end 14 a of the nanotube comes to be quitesharp, so that this cutting method can provide a probe 20 possessinghigher quality than the perpendicular cutting method shown in FIG. 5.The reason is that the more sharp is the tip end 14 a, the higher aresolution for a surface image of specimen increases.

[0061]FIG. 7 is a schematic diagram showing a method to improve thequality of the tip end of the nanotube. By irradiating the focused ionbeam I to the tip end region 14 c of the tip end portion 14 of thenanotube 12, ions are driven into the tip end region. According as anacceleration voltage applied to the focused ion beam, various casesoccur such that an ion film is formed on the surface of the tip endregion 14 c, the ions replace constituent atoms of the nanotube or fall,as solid solution, into holes of an atomic surface, and or the ions areinjected into an inner space of the tip end region 14 c.

[0062] In a case where, as the sort of the ions, for examples, fluorine,boron, gallium, or phosphorus, etc. are employed, these atoms react oncarbon atoms in the nanotube to form CF-combination, CB-combination,CGa-combination or CP-combination, which are caused to possess thespecific property corresponding to each combination. In a case where theions are ferromagnetic atoms such as Fe, Co, Ni, etc., ferromagnetism ofthe surface of a specimen can be detected at the atomic level.

[0063] Furthermore, the improvement of qualities of nanotubes includesthe case to give conductivity to an insulation BN series nanotube or theBCN series nanotube by shooting metal ions to them and inversely, alsothe case to give insulation property to a conductive carbon nanotube byshooting insulation substance to the nanotube.

[0064] It is needless to say that the present invention is not limitedto the above-described embodiments; and various modifications and designchanges, etc. within this limits that involve no departure from thetechnical spirit of the present invention are included in the scope ofthe present invention.

Industrial Applicability

[0065] According to the present invention of claim 1, a nanotube and acantilever are fastened to each other with a deposit which is made ofdecomposed component produced by decomposing organic gases using afocused in beam so that the fastness is quite firm, therefore, thepresent invention can provide a probe for a scanning type microscope inwhich the nanotube does not fall out from the cantilever in many timesrepeated use.

[0066] According to the present invention of claim 2, since ahydrocarbon gas is used as an organic gas, if the decomposed deposit ismade extremely thin so as to give the carbon film conductivity, thenanotube and cantilever are set in electrically connected state by meansof the conductive carbon film and a voltage can be applied to flowcurrent in the probe for the scanning type microscope.

[0067] According to the present invention of claim 3, since aorganic-metallic gas is used as an organic gas, the decomposed depositwith which the nanotube is fasten can be made a conductive metal film.By this strong conductive film, the nanotube and the cantilever arecertainly electrically connected, so that a voltage can be applied toflow current in the probe for the scanning type microscope.

[0068] According to the present invention of claim 4, since asemi-conduction silicon cantilever, an insulation silicon nitridecantilever or a cantilever coated with a conductive substance areutilized, by constructing a probe by means of combinations of thecantilever and nanotubes which possess various electric properties, thepresent invention can provide various probes for scanning typemicroscopes such as an insulation probe, semi-conductive probe, aconductive probe, etc.

[0069] According to the present invention of claim 5, since anunnecessary deposit heaped up at a nanotube probe needle is removed byirradiating an ion beam, the present invention can provide a clean probefor a scanning type microscope which develops the ability as isdesigned.

[0070] According to the present invention of claim 6, the presentinvention can provide a probe for a scanning type microscope, by whicherror information caused by an unnecessary deposit can be excluded bymeans of removing the unnecessary deposit at the tip end portion of ananotube probe needle, and furthermore for which a second process suchas a formation of a conductive film is easily performed by means ofremoving an unnecessary deposit near the base end portion.

[0071] According to the present invention of claim 7, since anunnecessary part of a nanotube is cut off by irradiating an ion beam,oscillation of the tip end portion of the nanotube probe needle iseliminated so that resolution for the surface image of a specimenincreases. Accordingly, the unification and increasing of the detectionefficiency of a probe for a scanning type microscopes are achieved.

[0072] According to the present invention of claim 8, in a case wherethe nanotube is perpendicularly cut, the section area is caused to beleast so that the section is formed to be neat, or in a case where thenanotube is obliquely cut, the tip end of the section is formed to bequite sharp, therefore, the probe can follow indentations andprojections on the surface of a specimen, as the result, the detectionresolution of the microscope increase.

[0073] According to the present invention of claim 9, since desired ionsare shot into at least the tip end of the tip end portion of thenanotube probe needle, physical and chemical properties of the nanotubetip end portion can be changed as desired. Accordingly, the presentinvention can provide a probe for a scanning type microscope whichsensitively reacts to specific physical and chemical actions from aspecimen so that the probe for the scanning type microscope detectsmagnetic force and organic function groups of the surface of thespecimen, and so on. For examples, by shooting ferromagnetic atoms intothe tip end portion such as Fe, Co, Ni, etc. magnetism of the specimenscan be effectively detected.

[0074] According to the present invention of claim 10, by injectingfluorine, boron, gallium, or phosphorus, etc. and by causing to combinethem with constituent atoms of the nanotube, the specific qualitiescorresponding to the combinations can be developed in the nanotube probeneedle.

[0075] Needless to say, the present invention of claims 5 though 10 allcan be applied to cantilevers accompanied with the nanotubes which aremanufactured by various apparatuses such as an electronic microscope ora focused ion beam apparatus.

1. A probe for a scanning type microscope which obtains substanceinformation of a surface of a specimen by a tip end of a nanotube probeneedle fastened to a cantilever, characterized in that a nanotube isfastened to said cantilever by a deposit of decomposed componentsproduced by resolving an organic gas by use of an ion beam in a focusedion beam apparatus.
 2. The probe for a scanning type microscopeaccording to claim 1, wherein a hydrocarbon gas is used as said organicgas.
 3. The probe for a scanning type microscope according to claim 1,wherein an organic-metallic gas is used as said organic gas.
 4. Theprobe for a scanning type microscope according to claim 1, wherein saidcantilever is a silicon cantilever, a silicon-nitride cantilever, or acantilever coated with a conductive substance.
 5. A probe for a scanningmicroscope produced by focused ion beam machining, characterized in thatan ion beam is irradiated to a predetermined region of a nanotube probeneedle fastened to a cantilever, thus removing an unnecessary matteradhering to said predetermined region of said nanotube probe needle. 6.The probe for a scanning type microscope according to claim 5, whereinsaid unnecessary matter is an unnecessary deposit heaped up at a tip endportion of said nanotube probe needle or an unnecessary deposit heapedup near a base end portion of said nanotube.
 7. A probe for a scanningmicroscope produced by focused ion beam machining, characterized in thatan unnecessary portion of a nanotube probe needle fastened to acantilever is cut off by irradiating an ion beam at a tip end portion ofsaid nanotube probe needle, thus controlling a length of said tip endportion of said nanotube probe needle.
 8. The probe for a scanning typemicroscope according to claim 7, wherein in cutting-off of saidunnecessary portion, said nanotube is cut in a perpendicular directionthereof or an oblique direction thereof.
 9. A probe for a scanningmicroscope produced by focused ion beam machining, characterized in thations are shot to a necessary portion of a tip end portion of a nanotubeprobe needle fastened to a cantilever, thus changing physical andchemical properties of said probe needle.
 10. The probe for a scanningtype microscope according to claim 9, wherein said ions are fluorine,boron, gallium, or phosphorus.